The plan ' following the Delhi and Mumbai models ' is to set up 50 CNG stations in and around the city.

While 10-12 new pumps will dot the periphery, about 40 existing pumps in strategic locations within the city will be readied for dispensation of CNG for public transport.

'We will set up a separate firm with an oil company for the project,' Banerjee told Metro after his meeting with the chief minister.

The pipeline connecting CNG stations can be extended to households and also to commercial users (industry).

PNG will be 10 per cent cheaper than cooking gas. Being a low-pressure gas, it is safer than LPG.

The cost to a consumer for domestic installation of PNG is about Rs 5,000-Rs 5,500 in Delhi. It goes down substantially in case of multi-storeyed buildings.

While supply of PNG to homes will be dictated by consumer choice, the successful migration of transport vehicles to CNG, like in Delhi, will depend on the political will of the Buddhadeb Bhattacharjee government.

'We need support from the state to implement the system. Without it, the process will be lengthy and the benefit limited,' Banerjee pointed out.

Till now, the Bengal government's record in cleaning the city's foul air has been abysmal.

Auto LPG trickling into a few pumps has amounted to nothing, and the chief minister has gone on record saying CNG could be the answer.

Now, if GAIL has its way, CNG ' and PNG ' should arrive in the city by 2008 through the 840-km pipeline, capable of carrying 12 million standard cubic metre of gas annually.

According to estimates, Calcutta will consume about 0.5 million standard cubic metres of gas a year.

But will the joint-venture company utilise the existing pipeline network of the state-owned Greater Calcutta Gas Supply Corporation Ltd'

Only if the loss-making unit is restructured, clarified Banerjee. Otherwise, the company will develop its own network in the city.